Dopamine release from nigral transplants visualized in vivo in a Parkinson's patient

Synaptic dopamine release from embryonic nigral transplants has been monito red in the striatum of a patient with Parkinson's disease using [C-11]-racl opride positron emission tomography to measure dopamine D-2 receptor occupa ncy by the endogenous transmitter. In this patient, who had received a tran splant in the right putamen 10 years earlier, grafts had restored both basa l and drug-induced dopamine release to normal levels. This was associated w ith sustained, marked clinical benefit and normalized levels of dopamine st orage in the grafted putamen. Despite an ongoing disease process, grafted n eurons can thus continue for a decade to store and release dopamine and giv e rise to substantial symptomatic relief.